More about adult education than concentration. While it does contain useful information about concentration, the bulk of this book focuses more so on the overarching subject of adult education and continued learning. Two, maybe three chapters include useful tips for better concentration, but the rest of the book is concerned with how to study, why study is important, how to pass exams, etc.
The book is written well, as books ought to be and used to be back when one needed a publishing house, and while the title is slightly misleading, it is an informative read.